Emergency Department Boarding, Crowding, and Error.

Objectives: Emergency department (ED) crowding and boarding have become a public health emergency. Independently, each is associated with morbidity and mortality, but what remains to be elucidated is whether there is an association between these 2 instances and a departmental error. Our objective is to examine adjudicated error as it relates to these 2 instances. Methods: We performed a retrospective cohort study, analyzing every patient encounter from July 1, 2018 to June 30, 2023 and queried for the presence and absence of an error. We calculated incident rate ratios and controlled for the patient's age, gender, Emergency Severity Index (ESI) level, the ED work score (a surrogate measure of crowding), and ED crowding surge capacity activation. Our primary exposures were crowding and boarding, and our outcome of interest was the presence of error. Results: Of 250,049 patient encounters, an error rate of 500/100,000 was observed, and there was an increase in both boarding and ED volume. There was a higher likelihood of error with patients whose status was boarding in the ED (adjusted incidence-rate ratios [aIRR] 1.60 [95% CI 1.42-1.82]) and who had higher acuity (ESI 1 IRR 2.9 [95% CI 2.4-3.5], and ESI 2 IRR 1.5 [95% CI 1.3-1.7]) when compared with encounters where no error occurred. There was a lower likelihood of error with a higher ED work score (aIRR 0.81 [95% CI 1.03-1.47]). Conclusion: In our retrospective cohort study of all ED encounters over the past 5 years, ED crowding and boarding increased but did not appear to portend a higher likelihood of an error. However, higher acuity patients, and those who were themselves boarders, had an increased likelihood of an error in their care.